In the design of PCB, many friends do not know enough about the layers in PCB, especially the novice, the role of each layer is vague. This time, let’s take a look at the AlTIumDesigner drawing board, what are the differences of each layer.

1. Signal layer

The signal layer is divided into TopLayer (TopLayer) and BottomLayer (BottomLayer), which have electrical connections and can place components and cables.

2. Mechanical layer

Mechanical is the definition of the appearance of the entire PCB board. The emphasis on “Mechanical” means that it has no electrical properties, so it can be safely used for drawing shapes, drawing Mechanical dimensions, placing text, and so on, without worrying about any changes to the electrical properties of the board. A maximum of 16 mechanical layers can be selected.

3. Screen printing layer

Top Overlay and Bottom Overlay are used to define the Top and Bottom screen printing characters. They are text symbols printed on Top of the solder resistance layer, such as component name, component symbol, component pin, and copyright, to facilitate circuit welding and error checking.

4. Tin paste layer

The solder Paste layer includes the Top Paste layer and the Bottom Paste layer, which refers to the surface Paste pad that we can see on the outside, that is, the part that needs to be coated with solder Paste before welding. So this layer is also useful in hot air leveling of the pad and making welding steel mesh.

5. Welding resistance layer

Solder layer is also often referred to as “windowing-out,” including TopSolder and BottomSolder, which play the opposite role to solder paste and refer to the layer to cover green oil. The layer is solder free to prevent short circuit of excess solder at adjacent joints during welding. The solder resistance layer covers the copper film wire and prevents the copper film from oxidizing too quickly in the air, but the position is set aside at the solder joint and does not cover the solder joint.

Conventional copper coating or wiring is the default cover green oil, if we correspondingly in the solder layer treatment, will prevent the green oil to cover, will expose the copper.

6. Drilling layer

The drill layer consists of DrillGride and DrillDrawing. The drill layer is used to provide information about the drill holes in the circuit board manufacturing process (such as pads, which need to be drilled through holes).

7, prohibit wiring layer prohibit wiring layer (KeepOutLayer) used to define the boundary of the wiring layer, after defining the prohibit wiring layer, in the future wiring process, with electrical characteristics can not exceed the boundary of the prohibit wiring layer.

8. Multi-layer

The pads and penetrating holes on the circuit board need to penetrate the whole circuit board and establish electrical connections with different conductive graphic layers, so the system specially sets up an abstract layer – multi-layer. Generally, pads and holes are set on multiple layers, and if this layer is closed, pads and holes will not be shown.